The present invention relates to a robot hand tool mounting device for mounting a tool such as a pneumatic chuck to a hand of an assembly robot installed in an automated assembly line of electronic equipment or other products.
An assembly robot is installed in an automated assembly line of electronic equipment or the like and one of various tools such as a pneumatic chuck is mounted to a hand of the assembly robot such that the one tool can be replaced by another according to operation. A tool mounting device for mounting the tool to the hand of such an assembly robot is generally formed of a tool adaptor to which the tool is mounted and a mounting unit which is mounted to the robot hand and to which the tool adaptor is detachably connected. To the mounting unit, a pair of clamp arms opened and closed by operation of air pressure and a return spring are provided. To a central portion of the tool adaptor, on the other hand, a connecting shaft having a locking flange at its top portion is provided and the mounting unit and the tool adaptor are connected to each other by clamping the connecting shaft between the clamp arms.
However, because the mounting unit and the tool adaptor are connected by the clamp arms extending from the mounting unit and the connecting shaft extending from the tool adaptor in the above prior-art tool mounting device, an axial length of the mounting device is increased and it is difficult to reduce a thickness of the mounting device. Furthermore, because the one connecting shaft positioned at the center of the tool adaptor is clamped between the clamp arms positioned at the center of the mounting unit, an axis is likely to incline.
On the other hand, it is required that such a tool mounting device should have a superior level of safety such that the tool adaptor is not detached and does not fall from the mounting unit if the air pressure for clamping reduces unexpectedly.
It is a technical object of the present invention to provide a robot hand tool mounting device which can reliably connect a tool adaptor and a mounting unit such that an axis does not incline and a tool does not fall off and which has a small thickness and excellent connecting accuracy and safety.
To achieve the above object, a tool mounting device of the invention comprises a tool adaptor to which a robot hand tool is mounted and a mounting unit which is mounted to a robot hand and to which the tool adaptor is detachably connected, wherein the tool adaptor has a plurality of connecting members engaged with jaw members of the mounting unit, the mounting unit has a rod that expands and contracts by operation of air pressure, the plurality of connecting jaw members disposed at regular angles about an axis of the rod and displaced in radial directions, a converting mechanism for converting an expanding/contracting operation of the rod to operations of displacement of the jaw members, and connecting locked portions formed at outer end portions of the respective jaw members, and each the locked portion has an inclined face which is inclined downward as it extends outward and which is engaged with the connecting member to draw the tool adaptor wedgewise and a stopper portion connected to the inclined face for preventing falling of the connecting member from the locked portion.
In the tool mounting device of the invention having the above structure, if the rod is actuated by operation of the air pressure and the plurality of jaw members are displaced outward in the radial directions through the converting mechanism, the inclined face of the connecting locked portion formed on the outer end portion of each the jaw member is engaged with the connecting member of the tool adaptor and the jaw member is displaced further to pull the connecting member up along the inclined face. As a result, the tool adaptor is drawn toward the mounting unit and connected to the mounting unit. At this time, while the tool adaptor is drawn toward the mounting unit, displacement of cores of the tool adaptor and the mounting unit from each other is corrected and the tool adaptor and the mounting unit are connected coaxially and reliably. Furthermore, because the tool adaptor and the mounting unit are connected at a plurality of points by engagement of the plurality of jaw members and the connecting members with each other, inclination of axes with respect to each other is not generated and high connecting accuracy can be obtained. Moreover, by wedge effect of the inclined faces, the connecting force is increased significantly.
If the air pressure for connecting reduces in a state in which the tool adaptor and the mounting unit are connected, each the jaw member is pushed back inward in the radial direction by load that acts on the inclined face through the connecting member. However, the stopper portion is provided to an outside of the inclined face and the connecting member stops in the position of the stopper portion when the connecting member reaches the position. Therefore, the connecting members are not detached from the jaw members, thereby reliably preventing falling of the tool adaptor.
In the tool mounting device, the plurality of jaw members that can be displaced in the radial directions are provided to the mounting unit, the inclined faces formed on the jaw members are locked to the connecting members of the tool adaptor, and the tool adaptor is pulled up wedgewise by the inclined faces and connected. Therefore, an axial length can be reduced and a thickness can be reduced as compared with the prior-art mounting device in which connecting is carried out by using the clamp arms and the connecting shaft.
According to a concrete embodiment of the invention, each the stopper portion includes a horizontal face or a reversely inclined face that is inclined reversely to the inclined face and an inward component of force of load that-acts on each the jaw member through each the connecting member is canceled in a position of the stopper portion.
According to another concrete embodiment of the invention, the converting mechanism includes a cam formed on one of the rod and the jaw member and a cam groove formed on the other and the cam and the cam groove are inclined with respect to the axis of the rod and are engaged with each other such that they can slide along the inclination.
According to yet another concrete embodiment of the invention, the tool adaptor and the mounting unit respectively have air connecting portions for connecting their air piping ports, a check valve elastically biased by a spring in a valve closing direction is mounted and a push rod elastically biased by a spring in such a direction that a tip end of the push rod projects from the connecting portion on the mounting unit is provided in the air connecting portion on the mounting unit, the push rod is pushed in by the tool adaptor to open the check valve when the tool adaptor and the mounting unit are connected, and the tool adaptor is forcibly separated by elastically biasing force of the spring when the tool adaptor and the mounting unit are separated from each other.